Fuel distributor with acceleration enrichment



March 5, 1963 H. R. sclBBI-z ETAL FUEL DISTRIBUTOR WITH AccELERATIoNENRICHMENT 2 Sheets-Sheet 1 Filed March 20, 1961 March 5, 1963 H. R.sclBBE l-:TAL 3,079,904

March 20, 1961 United States This invention relates to a fuel injectionsystem for high speed, four cycle, spark ignition internal combustionengines and is particularly concerned with a method and mechanism forincreasing the fuel delivered to the engine during periods ofacceleration.

In an embodiment of the invention fuel is delivered from a variableoutput metering pump such as that having a plurality of pistonsoperating at a variable stroke. The pump delivers to a distributor whichprovides for periodic releases of the fuel to lines leading to fuelinjectors. In a conduit means between the pump and the distributor isconnected an accumulator chamber which has a movable wall biased todischarge to the distributor for each fuel release and to accumulatefuel from the metering pump between releases. An acceleration enrichmentchamber is also connected to communicate with the conduit means betweenthe pump and accumulator and to be lled with fuel from the pump and beemptied to supply its fuel to the distributor for increasing the fueldelivered by the distributor during periods of acceleration of theengine. In automobile operation the enrichment chamber is connected tothe accelerator pedal of the automobile to enrich the fuel deliveryduring acceleration.

It is a general object of the invention to provide an improved fueldelivery system for an engine supplied with hiel through injectors.

A further object of the invention is to provide an irnproved fuelinjection system employing a pump having a pulsating output wherein thepulsations are smoothed and a uniform delivery of fuel to the engine isaccomplished by delivering equal and uniform quantities of fuel to eachengine cylinder for each release of a distributor which receives thedelivery from the pump.

A further object of the invention is to provide a mechanism forenriching the fuel delivered to an engine during acceleration periods bystoring fuel delivered from the pump and selectively delivering thisstored fuel to the distributor such as during acceleration.

A further object of the invention is to provide an improved accelerationenrichment mechanism for a fuel injector system which enhances theresponse of the engine without adding to the flow rate as controlled bya variable displacement pump and therefore without sacrifice to thegeneral fuel economy.

A still further object of the invention is to provide a pump anddistributor for delivering fuel to an injector supplied engine with anaccumulator between the pump and distributor which has a completedischarge for each release of fuel by the distributor and which isconstructed so that air or fuel vapor can be readily purged and are nottrapped in the accumulator to detract from its operation.

Other objects and advantages will become more apparent with the teachingof the principles of the invention in connection With the disclosure ofthe preferred embodiment thereof in the specification, claims anddrawings, in which:

FIGURE 1 is a sectional view taken through the center of a fuelsupplying mechanism in accordance with the principles of the presentinvention, for delivering fuel to an injector supplied engine;

3,079,904 Patented Marl 5, 1953 FIGURE 2 is a vertical sectional linetaken substantially along line II-II of FIGURE l; and

FIGURE 3 is a vertical sectional view taken substantially along lineIII-III of FIGURE l.

As shown on the drawings:

FIGURE l illustrates a mechanism having a pump 10 with a variabledelivery for pumping fuel. The fuel flows to a distributor 11 which atintermittent periodic intervals releases the pumped fuel to individualfuel injectors 14 which supply an internal combustion engine. The fuelflows from the pump to the distributor through a conduit means 12 andcommunicating with the conduit means is an accumulator 13 which collectsthe fuel from the pump between distributor releases and completelydischarges its collected fuel during the periods of distributor release.

Also communicating with the conduit means 12 is an enrichment device 15which is lled with fuel from the metering pump 10 and selectivelydischarges this fuel to the distributor 11 when the engine isaccelerated.

The metering pump 10 and distributor 11 are incorporated in a unithousing 16 made up of parts which are suitably clamped together such asby cap screws or bolts with the parts having gaskets therebetween. Theseparts need not be described in detail inasmuch as their constructionWill be apparent from the drawings and the entity may be generallyreferred -to as the housing 16. The housing is adapted to be suitablymounted on an engine to be driven thereby such as by being connected tothe timing shaft. The mechanism has a distributor shaft 17 which isdriven at one half the speed of an engine to which fuel is delivered sothat in a four cycle engine the distributor 11 will release fuel oncefor one injection per four stroke cycle of the typical multicylinderengine.

Fuel is received through a line connected to a fuel intake opening 18 inthe housing 16 and usually fuel being delivered to the apparatus from afuel tank by a supply pump so that the intake 18 will receivepressurized fuel. The distributor is connected to individual fuel lines19a which lead to the injectors 14.

The metering pump 10 is driven from the distributor shaft 17 which issupported in the housing 16 in a ball bearing assembly 18 and -acylindrical bearing surface 19.. A circular sealing ring 20 ispositioned around the shaft in the housing to prevent the escape oflubricant and a ring 21 is also positioned around the shaft to preventthe escape of fuel from the distributor 11, as will later be described.

The pump 10 is driven by a gear 22 on the shaft 17 driving a gear 23pinned to the pump shaft 7.4 which is supported in a ball bearingassembly 25.

The ratio of the gear 22 on the shaft -17 to the gear 23 on the pumpshaft is preferably one which cannot be expressed exactly in wholenumbers, such as 23/ 30 or 30/23; 25/28 or 28/25; 20/33 or 33/20.Inasmuch as the pump is a piston type, such fractional gear ratios willpreclude the possibility of any one piston consistently delivering fuelthrough the same port of the distributor and hence to the same enginecylinder. If small differences exist between the pistons, pistonchambers, piston stroke links or seals of the pumping element 'a slightinequality of fuel delivery may occur between pistons and this will notconsistently result in the inequality being reected in the fueldelivered to one or more engine cylinders but will move through thesequential injections to all of the cylinders. For example, enginefailures due to consistently lean mixtures on one cylinder of the engineare prevented. While excessively rich or lean injections could occur dueto manufacturing differences, these conditions will move through all ofthe cylinders of the multicylinder engine,

The bearing 25 forthe pump shaft'24 and the pump pistons are lubricatedthrough a lubrication connection 26 in the housing and lubricant flowsthrough suitable passages through a passage 27 to the bearing 25 andthrough passages such as 28 Vleading tothe individual pump .pistons andtheir seals. Lubricant is also delivered to the hollow chamber -33 whichcontains the mechanism for driving the pump pistons.

As shown in FIGURES l and 3, the pump is provided with three radiallyextending pistons 29, 30 and 3,1 slidably supported in radially boredcylinders 29a, 35a and 31a Vin the housing 16. An odd number of pistonsare provided and a greater number may .be employed if desired retainingan odd number. The pistons are movable radially outwardly in a dischargestroke and radially inwardly in an intake stroke and are urged inwardlyby springs such as 32 surrounding the inner ends of the pistons andseated in annular recesses in the wall of the chamber 31. Split snaprings 34 seat in 'annular grooves in the pistons to hold washers againstwhich the springs engage.V inasmuch' as the construction of each pistonis the same, fthe arrangement of the piston 30 only need be described indetail.

A The pistons are driven by a head 35 eccentrically carried at the lowerend of the pump shaft 24. The head 35 rotatably supports a roller 36which is rotatably mounted n a stud 35a on the head and the roller 36rolls on the stud to reduce friction -between the roller and pistons. IThehead 35 is carried in a radially extending supporting slot' 37 on theshaft 2'4 and its eccentricity with respect tothe axis of the shaft iscontrollable by a bell crank 38 supported on the shaft. The lower arm ofthe bell crank is held in a recess 39 in the head 35 and the upper armof the bell crank 39 is received in a recess 40 in a plunger 41coaxially carried in the hollow center ofthe pump shaft 24. A cross pin41a extends across through an axially elongated slot y41b in the plunger41 and the pin 41a is mounted in the shaft 2'4. This -pin 41a alsofunctions to lock the gear 23 to the pump shaft. A spring 42 inlanVaxially extending. recess in the end of the shaft 2'4 engages theunderside of 'an enlarged head 41e of the plunger 41 to` urge' it to theleft, as shown in FIGURE 1. This tends to move the' head 35 to increasethe eccentricity thereof and' increase the pump delivery. The action ofthe spring 42 is resisted lby an arm 43 bearing on the upper end of thehead of the plunger 41 and mounted on a shaft v44. The shaft 44 is.connectedV to the fuel control mechanism shown schematically at y45.

The fuel control mechanism 45 will determine the displacement and outputof the metering pump and is 5 operated in accordance with variousfactors of engine conditions such as' the intake manifold pressure andengine temperature. A manual input signal is also provided by anaccelerator shown schematically at 46.

Each Vof the pump plungers are sealed -by an O-ring 47 in `an annulargroove 47a in the` housing. The Width of the groove in an axialdirection is greater than the cross `sectional diameter of the O-ring.The inner diameter of theelastic O-ring is` slightly greater than thediameter of the -pistonv3tl'and the outer diameter of the O-ring isslightly greater than thediameter offthe base of the .groove 47a. Whenassembled, the radial compression of the outer diameter of the elasticO-ring forces the inner diameter of the ring to contact the cylindricalpiston surface. Dimensions of` the Oring, O-ring groove, and

.piston are so .designed that contact of the inner ldiameter Vof theO-ring with` `the piston is sucient to sealagainst the uid fuelvpressure but light enough to preventexcessive friction duringreciprocation of the piston-within the seal.V The cylindrical bore orcylinder 30a in which the 4'piston slides is relieved at its outer endVso as to be of a .slightly'larger size than thel inner end to therebyprevent scratching of the piston at the location where the piston slidesthrough the O-ring y47. This insures that the piston willl retain itsfinish at that/.location and not wear the 4 O-ring but retain a vgoodseal. Lubricant enters the cylinder 36a behind the O-ring seal.

As shown in FIGURES l` and 3, the fuel enters the intake 1S of thehousing andV flows through a passage 49 that forms a loop. Oi .this loopare branch passages 50, 51 and 52 for supplying pumping chambers 43 atthe end of the pump pistons. Fuel intake into the pump pistons. Fuelintake into the pump ch-ambers y48 flows through `an intake pont 51apast a check valve having'a ball check 53 held by a spring `54 against aseat 55 so `as to close the intake passage when the pump piston movesoutwardly. Flow out of the pumping chamber 48 is through a port 56a pasta ball check valve 5611 which closes during the intake stroke of thepiston. The ball valves 53 `and 56hY may also be rubber" disc checkvalves.

Delivery from theV pumping chamber 48 is through a passage 56 leading upinto a chamber 57 in which is located a distributor plate 58. Thepassage 56 and the chamber 57 constitute the conduit means leading fromthe pump discharge to the distributor.

It is to lbe noted that the pumping chamber receives `iluid through theport 51a: and delivers huid through the port 56a. These ports and thepassageways connected thereto are arranged so that fluid flow throughthe pumping chamber 4S is in an upward direction thus facilitating theescape flow of fluid vapor and entrained air through the chamber. All ofthe fluid passages in the pump are designed to prevent the trapping offuel vapor or entrained air in the pumping elements. This makes the pumpselfpurging of vapor and air and greatly reduces the number of pumprevolutions required to purge a vapor locked pump. l

As shown in FIGURES 1 and 2, a distributor platev 58 has a at smoothundersurface which sealingly slides against a surface 59 in the chamber57 and is held downwardly by a spring 60 and is driven by the shaft 17.Below the distributor plate 58 in the stationary housing part are aseries of evenly spaced circumferentially arranged relief ports 62 whichconduct fuel each time an elongated port -61 in the distributor plate 58passes over them. This inter- Y mittentlyY at even intervals relievesthe uid `fuel from the distributor chamber 57 and the fuel sequentiallyilows' out through the lines 19 to the individual injectors 14.

The accumulator 13 which is in communicationrwith the conduit means 12vbetween the pump and distributor has an expansible chamber in the formof a cylinder 63 in which is located a piston 64. The piston is springloaded by a spring 66 which urges the piston 64 in a direction todischarge the fuel from the chamber 63. An annular piston seal 65surrounds the piston.

The spring 66 has a natural frequency greater than the accumulatorexciting frequency, namely the opening and closing of the successivedistributor ports. The accumulator thus empties itself for each' releaseof the distributor.

The accumulator 13 is llocated below the distributor chamber and in aposition so that air or fuel vapor cannot -be trapped. The cylinder 63is shown ini a liori'- zontal position below the distributor.

Also in communication with the distributor chamber 57, or in otherWords, in' communication' with the conduit means 12 between the pump anddistributor, is an accelerator chamber shown in the form of an elongatedcylinder 67. The chamber 67 communicates with the distributor chamber 57through openings 72 through the distributor plate. Within the chamber 67is a piston V68 having a smooth surface 59 by a coil spring 60 and theflow of fuel through the passages 72 has no effect on the normaloperation of the distributor.

The use of this accelerator chamber 67 enhances the response of theengine to movements of the accelerator pedal 46 Without adding to theflow rate through the variable displacement pump 10. This thereforeoccurs without sacrifice to the general fuel economy. It is also to benoted that as the accelerator is released, the variable chamber 67provides an escape chamber for the fuel in the distributor therebyenhancing the rapid cut-off of fuel supplied to the engine as theaccelerator is released to prevent delivering an over enriched fuelmixture to the engine and consequent smoking and increase in smogeffects.

The accelerator cylinder 67 is preferably slightly smaller in diameterthan the accumulator cylinder 63 but the piston 68 has a greater axialmovement than the accumulator piston 64.

While the fuel injection nozzles .may be of various designs, the nozzle14 is shown schematically as including an injection opening 74 againstwhich seats a valve member 73 held against the opening by a tensionspring 75. The tension spring 75 is such that it opens at a lower fuelpressure than that required to depress the accumulator spring 66. Thuswith the accumulator discharge pressure being greater than the injectornozzle opening pressure, the injector will open as soon as thedistributor 11 releases the fuel and will stay open during the time theaccumulator piston 64 is emptying the accumulator chamber and during thetime the distributor ports are in alignment.

As a brief summary of operation, the power or distributor shaft 17 isdriven from the engine to provide a fuel release for each fuel intakestroke of the engine, and through the gears 22 and 23 drives the pump10. The delivery of the pump is varied by the arm 43 pushing down on theplunger 41 which determines the eccentricity of the head 35 and thestroke of the pump pistons 29, 30 and 31. Fuel flows in through theintake 1S past the intake check valve 53 on the intake stroke of thepiston Sil and a check valve 5617, FIGURE 1, closes oi the deliverypassage 56. On the delivery stroke of the piston fuel flows through thepassage 56 to the distributor chamber 57. As the distributor plate 5Srotates quantities of fuel are intermittently released as the port 61successively aligns itself with the ports 62. The accumulator chamber 63receives fuel between port releases and discharges during the releaseperiods. The acceleration enrichment chamber 67 will fill with fuel fromthe pump and when the accelerator 46 is depressed an enrichment quantityof fuel will be discharged by the piston 68 into the distributor chamber57 to be delivered to the individual injectors 14.

Thus it will be seen that we have provided an improved pump anddistributor arrangement incorporating a fuel enrichment system whichmeets the objectives and advantages above set forth. The arrangementlends itself to a compact unit device capable of continued operationwithout adjustment. Fuel enrichment is simply and easily accomplished toimprove the performance of the engine without adversely affecting normaloperation or affecting the fuel economy.

The multiple piston metering and pressure generating pump has anadvantage in freedom from high speed limitations that are placed on asingle piston injection pump that must reciprocate through one strokefor each cylinder of a multi-cylinder engine. The metering pump with arotary distributor has considerable manufacturing advantages over typesheretofore used requiring individual pistons, cylinders, valves andpassages all of which must be precisely matched to maintain distributionequality for each cylinder of a multicylinder engine.

It will lbe understood that while the distributor usually is employed toaccomplish one fuel release and one injection per four stroke cycle itmay also be used to provide two injections per four stroke cycle. Thismethod of distribution halves the large fuel quantities required percycle and precludes the necessity for larger metering pump components.

The drawings and specication present a detailed disclosure of thepreferred embodiments of the invention, and it is to be understood thatthe invention is not limited to the specific forms disclosed, but coversall modications, changes and alternative constructions and methodsfalling within the scope of the principles taught by the invention.

We claim as our invention:

l. A fuel supply mechanism for an engine fuel injection systemcomprising a variable delivery fuel pump, a distributor connected toreceive fuel from the pump for distributing the fuel to fuel injectors,a fuel conduit means connected between the pump and distributor for theflow of fuel from the pump to the distributor, an

expansible enrichment chamber communicating with said` fuel conduitmeans for filling with fuel from the pump, and means operable duringoperation of the supply mechanism selectively discharging fuel from saidexpansible enrichment chamber back into said conduit means fortemporarily increasing the fuel quantity delivered to the injectors.

2. A fuel supply mechanism for an engine fuel injection systemcomprising a variable delivery fuel pump, a distributor connected toreceive fuel from the pump for distributing the fuel to fuel injectors,a fuel conduit means connected between lthe pump `and distributor forthe flow of fuel from the pump to the distributor, an expansibleenrichment chamber communicating'with said fuel conduit means forfilling with fuel from the pump, means for selectively discharging fuelfrom said expansible enrichment chamber back into said conduit means fortemporarily increasing the fuel quantity delivered to the injectors, and`an -accelerator control for expanding and contracting said enrichmentchamber to fill with fuel from the pump or to temporarily increase thefuel quantity delivered to the injectors.

3. A fuel supply mechanism for an engine fuel injec- -tion systemcomprising pump means having a discharge for delivering fuel, adistributor having an intake connected to said pump discharge to receivefuel from the pump and to deliver fuel to `individual nozzles inmeasured quantities, acceleration enrichment means connected betweensaid pump discharge and said distributor intake to selectively deliveran additional acceleration quantity of fuel, and means for positivelyoperating said enrichment means :at selected times during operation ofthe system.

4. A fuel supply mechanism for an engine fuel injection systemcomprising a fuel distribution means for delivering fuel in measuredquantities to fuel injectors including a fuel pump With a deliverypassage, a-n enrichment chamber communicating with the pump deliverypassage `and being filled with fuel from the pump, and means forselectively immediately discharging fuel accumulated in said chamberback into said delivery passage for enriching the flow of fuel from thepump at a freely selected time.

5. In a fuel supply mechanism for an engine fuel injection system havinga fuel supply pump with a discharge and a fuel distributor connected tothe pump discharge and having outlets for connecting to individual fueldistribution points for distributing fuel from the pump, the improvementof an auxiliary fuel supply means connected to the distributor forimmediately and positively selectively supplying additional fuel forselective periods of engine operation.

6. A fuel supply mechanism for an engine fuel injection systemcomprising a fuel supply pump with a discharge, a fuel distributorconnected to the pump discharge a-nd having outlets for connecting toindividual fuel distribution points for distributing fuel om the pump,auxiliary fuel ysupply means connected to the distributor for supplyingadditional fuel, and means for instantaneously selectively operatingsaid auxiliary fuel supply means for furnishing enrichment fuel toanengine for selective periods of engine operation.

7. In a fuel supply mechanism for an engine fuel injection system havinga fuel supply pump with a discharge and a fuel distributor connected tothe pump discharge and having outlets for connecting to individual fueldistribution points for distributing fuel from the pump, the improvementof an acceleration enrichment fuel supply means connected to thedistributor, a speed control member for an engine movable in anacceelratingl direction and a decelerating direction for a manual inputsignal to increase or decrease the speed of the'engine, and meansconnecting the speed control member to said enrichment fuel supply meansfor operating the enrichment means to increase the delivery of fuel tothe engine when accel-` erating.

8. A fuel supply mechanism for an engine fuel injection systemcomprising a Variable delivery fuel pump, a distributor to receive fuelfromthe pump for periodically releasing fuel from the pump to injectornozzles, a fuel conduit means connecting between the pump anddistributor for the ow of fuel, an accumulator chamber communicatingwith said conduit means and having a yieldable wall accommodating theflow of fuel intothe chamber between distributor releases, means biasingsaid wall to completely discharge said accumulator chamber with eachrelease from the distributor, an expansible enrichment chambercommunicating with said conduit means for filling with fuel from thepump, and means for selectively discharging fuel from said expansibleenrichment chamber back into said conduit means for temporarilyincreasing the fuel quantity delivered to the injectors.

9. A fuel supply mechanism for an engine fuel injec# tion systemcomprising a variable delivery fuel pump', a distributor connected toreceiveV fuel from the pump for distributing the Afuel Vto fuelinjectors, a fuel conduit means connected between theV pump anddistributor 'for theY flow of fuel from the Vpump to the distributor, acylindrical accumulator cham-ber communicating with said conduit meansand having an accumulator piston in said chamber, -a spring biasing thepiston to discharge from the chamber having a natural frequency greaterthan the frequency of the' distributor to fully discharge theaccumulator chamber with each release of the' distributor, Aacylindrical enrichment chamber communicating with said conduit means andhaving a pistonA in said enrichment chamber, said enrichment chamberbeing of a smaller diameter than said accumulator chamber, and anenrichment piston in said enrichment chamber having a stroke `greaterthan the stroke of the accumulator piston and selectively operable toYincrease )the fuel delivered by the distributor.

' 10. A` fuel supply mechanism for -anengine fuel injection systemcomprising a variable deliveryY fuel pump, a distributor connected toreceive fuel from the pump for distributing the fuel to fuel injectors,a fuel conduit means connected between 'the pump and distributor lforthe ow of fuel from the pump to the distributor, a cylindricalaccumula-tor chamber communicating with said conduit means and having anaccumulator piston in said chamber, a spring biasing the piston todischarge from the chamber having a natural frequency greater than thefrequency of the distributor to fully `discharge the accumulator chamberwith each release of the distributor, a cylindrical enrichment chambercommunicating with said conduit means and having a piston in saidenrichment chamber, an enrichment piston in said enrichment chamber, andan accelerator connected to said enrichment piston for selectivelyoperating the piston to increase the fuel delivery by the distributorduring acceleration periods and decrease ythe fuel delivered by thedistributor during deceleration periods. 1 l1. A fuel supply lmechanismfor an engine fuel injectionsystemcomprising a fuel pump, a distributorconnected to receive fuel from the pump Ifor releasing fuel from 'thepump to fuel injectors at periodic intervals, a fuel conduit meansconnected between the pump and distributor for Vthe flow of `fuel fromthe pump to the' distributor, and means rconnected to said fuel conduitmeans for-receiving fuel from the conduit means during decelerationperiods to reduce the fuel quantity delivered by the distributor to theinjectors.

l2. The method of providing for acceleration fuel en richment in a fuelinjection systemhaving a variable output pump connected -to deliver to adistributor which comprises accumulating a quantity of fuel delivered bythe pump for the distributor and returning the accumulated fuel Ito thedistributor during periods of accelera-V tion ofthe engine.

13,. The method of providing for acceleration fuel en'- richment in afuel injection system having a variable outputpump connected -to deliverto a distributor which comprises accumulating `a quantity of `fuel`delivered by the pump for the distributor and selectively returning theaccumulated ifuel to the distributor at selected times.

References Cited in the ile of this patent FOREIGN PATENTS

1. A FUEL SUPPLY MECHANISM FOR AN ENGINE FUEL INJECTION SYSTEMCOMPRISING A VARIABLE DELIVERY FUEL PUMP, A DISTRIBUTOR CONNECTED TORECEIVE FUEL FROM THE PUMP FOR DISTRIBUTING THE FUEL TO FUEL INJECTORS,A FUEL CONDUIT MEANS CONNECTED BETWEEN THE PUMP AND DISTRIBUTOR FOR THEFLOW OF FUEL FROM THE PUMP TO THE DISTRIBUTOR, AN EXPANSIBLE ENRICHMENTCHAMBER COMMUNICATING WITH SAID FUEL CONDUIT MEANS FOR FILLING WITH FUELFROM THE PUMP AND MEANS OPERABLE DURING OPERATION OF THE SUPPLYMECHANISM SELECTIVELY DISCHARGING FUEL FROM SAID EXPANSIBLE ENRICHMENTCHAMBER BACK INTO SAID CONDUIT MEANS FOR TEMPORARILY INCREASING THE FUELQUANTITY DELIVERED TO THE INJECTORS.